This disclosure relates to voltage signal peak level detection used in sensor devices, namely in Fly-Height Sensors (FHS) devices, and circuitry used therein.
Hard Disk Drives (HDD) are ubiquitous in the computing environment. Existing HDD systems employ magnetic-medium-based storage devices, and the data is typically stored on circular, concentric tracks on magnetic disk surfaces. A read-write head retrieves and records data on the magnetic layer of a rotating disk as it flies over the disk surface without contacting the disk surface. When retrieving data, magnetic field variations are converted into an analog electrical signal, the analog signal typically is amplified, converted to a digital signal and interpreted. To guarantee the quality of the information saved on and read back from the disk, and to prevent damage of the head with disks spinning at high speeds, the read-write head should be accurately distanced from the disk. FHS devices are typically employed to detect the fly-height distance of the head from the disk during operation of the disk drives. Existing FHS systems utilize peak detection techniques in order to detect changes in sensor signal strength which are correlated to a distance of the sensor from the disk, for example. Inasmuch as accurate positioning of the sensor from the disk is necessary to guarantee the quality of information stored and read back from a disk, the accuracy of peak detection thus is essential to the function of the FHS devices. Design tradeoffs between speed, accuracy, and linearity of typical peak detection circuitry can limit the performance of some FHS devices.